The low-bush, wild blueberry is widely harvested in the United States. These plants, found in various locations in the United States, particularly Maine, grow in rocky, hilly terrain, which makes mechanization of their harvesting extremely difficult. This difficulty is compounded because these wild berries grow close to the ground in untilled and untillable fields, bearing their fruit about 3 to 12 inches above ground level, and when laden with berries or beaten down by rain, some of the plants may lie on the ground.
The deliciousness of the wild blueberry, however, has led to its being harvested and sold extensively in spite of these difficulties. Prior art methods for harvesting low-bush wild blueberries primarily include the use of hand rakes. These hand rakes typically have a short handle and a receptacle behind fine, flexible tines. The rakes are approximately 12 to 20 inches wide, with the tines spaced across the width. Each tine is solid, about 1/8 inch in diameter and about 10 inches long, with about 3/16 inch between each pair of adjacent tines. A worker, stooping over the bushes, runs the rake through each bush area 2 or 3 times, combing the bushes and stripping off the berries. When the rake receptacle is full, the worker dumps its contents into a pail or box.
The use of these hand rakes has many drawbacks. Not only is the labor backbreaking and time-consuming, but it is wasteful. The need for more than one pass knocks some berries to the ground and they are lost, plus many blueberries are left behind on the bush. Consequently, 20% or more of each harvest is lost. Moreover, a very high percentage of debris, such as stems and other plant parts, is harvested along with the blueberry crop. This necessitates extensive winnowing steps later to prepare a product suitable for sale to consumers.
Attempts have been made to mechanize the harvesting of wild blueberries, but these have primarily involved the arrangement and movement of hand-type rakes in ferris wheel fashion to imitate the action of hand rakes. Such arrangements do not reduce many of the drawbacks mentioned with respect to hand rake harvesting, and some problems, such as damage to plants, are increased. Also, these prior art machines are particularly damaging to young plants that spread and grow in areas recently treated with herbicides. Also, these machines are unable to adjust to the hilly terrain in which the wild blueberry grows, and their complicated, moving parts are subject to damage in the obstacle-filled, stony fields in which they must operate.